Herbert M. Pinedo

A CD34+ human cell line model of myeloid dendritic cell differentiation: evidence for a CD14+CD11b+ Langerhans cell precursor

The study of early events in dendritic cell (DC) differentiation is hampered by the lack of homogeneous primary cell systems that allow the study of cytokine‐driven, transitional DC differentiation steps. The CD34+ acute myeloid leukemia cell line MUTZ‐3 displays a unique ability to differentiate into interstitial DC (IDC) and Langerhans cells (LC) in a cytokine‐dependent manner. Phenotypic characterization revealed MUTZ‐3 to consist of three distinct subpopulations. Small CD34+CD14−CD11b− progenitors constitute the proliferative compartment of the cell line with the ability to differentiate through a CD34−CD14−CD11b+ stage to ultimately give rise to a morphologically large, nonproliferating CD14+CD11bhi progeny. These CD14+CD11bhi cells were identified as common, immediate myeloid DC precursors with the ability to differentiate into LC and IDC, exhibiting characteristic and mutually exclusive expression of Langerin and DC‐specific ICAM‐grabbing nonintegrin, respectively. The identity of the MUTZ‐3‐derived LC subset was confirmed further by the presence of Birbeck granules. We conclude that the MUTZ‐3 cell line provides a ready and continuous supply of common myeloid precursors, which should facilitate further study of the ontogeny of myeloid DC lineages.

Preoperative [18F] FDG–PET after chemotherapy in locally advanced breast cancer: prognostic value as compared with histopathology

BACKGROUND Established prognosis-based criteria determine the need for further treatment after primary surgery for breast cancer. Such criteria are lacking after neo-adjuvant chemotherapy. We determine the prognostic value of preoperative [(18)F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography ((18)FDG-PET) after chemotherapy in locally advanced breast cancer (LABC), both as independent indicator and as add-on to postoperative histopathology. PATIENTS AND METHODS Preoperative PET was carried out in 40 LABC patients. Two expert readers assessed residual (18)FDG uptake in the primary tumor. At histopathological examination of the surgical specimen, chemotherapy response was graded using the Honkoop criteria. Cox proportional hazards analysis was used to determine prognostic relevance of PET and histopathology. RESULTS Median follow-up was 60 months (range 15-94), during which 13 patients had recurrent disease, eight of whom died. (18)FDG uptake in the primary tumor was inversely related with disease-free survival (DFS) [hazard ratio (HR) 4.09; 95% confidence interval (CI) 1.26-13.31; P = 0.02] and this was superior to histopathology (HR 2.52; 95% CI 0.77-8.23; P = 0.13). Observer agreement of PET was excellent (intraclass correlation coefficient 0.88). Multivariate Cox regression revealed no added value of histopathology versus PET results. CONCLUSION (18)FDG uptake in the primary tumor at PET was inversely associated with DFS and may help to guide adjuvant therapy.

Extended neoadjuvant chemotherapy in locally advanced breast cancer combined with GM-CSF: effect on tumour-draining lymph node dendritic cells

The effect of long-term administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) on dendritic cell (DC) activation and survival in patients with locally advanced breast cancer (LABC) was studied. To this end, the number of activated DC (i.e. positive for the marker S100) in tumour-draining lymph nodes (TDLN) was determined and compared between LABC patients receiving neoadjuvant chemotherapy with GM-CSF (n=52) or without GM-CSF (n=11), and a control group of chemonaïve breast cancer patients (n=10). A significantly higher mean percentage of S100+ DC in the TDLN of the GM-CSF-treated patients (9.9%) was found compared with each of the respective control groups (5.3 and 5.1%, P=0.002). Moreover, intrapatient comparison before and after treatment showed that the percentage of S100+ DC significantly increased over the course of the GM-CSF treatment (P=0.018). In a univariate survival analysis with a median follow-up of 64 months, relatively high percentages of S100+ DC (> or =8%) were associated with a longer disease-free survival (DFS) (P=0.078). In patients with a high tumour load, where immunosuppressed conditions generally prevail, long-term administration of GM-CSF may thus contribute to survival through enhanced DC activation and consequently improved chances of effective antitumour immunity.

IL-10 conditioning of human skin affects the distribution of migratory dendritic cell subsets and functional T cell differentiation

In cancer patients pervasive systemic suppression of Dendritic Cell (DC) differentiation and maturation can hinder vaccination efficacy. In this study we have extensively characterized migratory DC subsets from human skin and studied how their migration and T cell-stimulatory abilities were affected by conditioning of the dermal microenvironment through cancer-related suppressive cytokines. To assess effects in the context of a complex tissue structure, we made use of a near-physiological skin explant model. By 4-color flow cytometry, we identified migrated Langerhans Cells (LC) and five dermis-derived DC populations in differential states of maturation. From a panel of known tumor-associated suppressive cytokines, IL-10 showed a unique ability to induce predominant migration of an immature CD14+CD141+DC-SIGN+ DC subset with low levels of co-stimulatory molecules, up-regulated expression of the co-inhibitory molecule PD-L1 and the M2-associated macrophage marker CD163. A similarly immature subset composition was observed for DC migrating from explants taken from skin overlying breast tumors. Whereas predominant migration of mature CD1a+ subsets was associated with release of IL-12p70, efficient Th cell expansion with a Th1 profile, and expansion of functional MART-1-specific CD8+ T cells, migration of immature CD14+ DDC was accompanied by increased release of IL-10, poor expansion of CD4+ and CD8+ T cells, and skewing of Th responses to favor coordinated FoxP3 and IL-10 expression and regulatory T cell differentiation and outgrowth. Thus, high levels of IL-10 impact the composition of skin-emigrated DC subsets and appear to favor migration of M2-like immature DC with functional qualities conducive to T cell tolerance.

Rapid disappearance of deoxyribose-1-phosphate in platelet derived endothelial cell growth factor/thymidine phosphorylase overexpressing cells.

Platelet derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) catalyzes the phosphorolysis of thymidine (TdR) to thymine and deoxyribose-1-phosphate (dR-1-P) and has a pro-angiogenic effect for which dR-1-P may be responsible. Using a purine nucleoside phosphorylase based assay it was found that TdR incubation did not increase dR-1-P accumulation in colon cancer cell line Colo320 and its PD-ECGF/TP transfected variant Colo320TP1. The assay was linear up to 25,000pmol dR-1-P with complete recovery of dR-1-P from cellular extracts. There was a huge discrepancy between thymine production and the measured dR-1-P level, 0.05% of the expected value for dR-1-P was found, indicating that there was a rapid disappearance of dR-1-P. However, in cellular extracts, TdR incubation increased dR-1-P, measurable by trapping, which was inhibited by a thymidine phosphorylase inhibitor. dR-1-P directly added to cellular extracts disappeared within 5-10min. In conclusion, large amounts of dR-1-P are produced by Colo320TP1 cells, which rapidly disappear thus not resulting in a net accumulation of dR-1-P in these cells.

Polymorphisms in the enhancer region of the thymidylate synthase gene are associated with thymidylate synthase levels in normal tissues but not in malignant tissues of patients with colorectal cancer.

BACKGROUND The enhancer region of the thymidylate synthase (TS) gene (TSER) contains a polymorphic tandem repeat sequence (2 or 3 repeats, 2R or 3R) and a single-nucleotide polymorphism (G > C) within the second repeat of the 3R alleles which might influence TS expression/activity and response to fluoropyrimidines. However, clinical studies in patients with colorectal cancer (CRC) failed to find a consistent relationship between TSER polymorphisms and protein levels as well as with clinical outcome. The analysis of the relationship between TSER genotype and TS mRNA and activity in normal and malignant tissues might explain the previous controversial data and help in the selection of useful markers to predict drug response and/or toxicity. MATERIALS AND METHODS To address this issue, we studied TSER genotype, TS expression, and activity with specific polymerase chain reaction and activity assays (TS catalytic activity and FdUMP binding) in normal (liver, mucosa) and malignant (primary tumor and liver metastasis) tissues from 83 patients with CRC. RESULTS No correlation between TSER genotype and TS mRNA and protein levels was observed in malignant tissues. In contrast, normal tissues harboring one or two 3RG alleles were characterized by higher TS protein levels (2.4-fold; P = .008) and catalytic activity (P < .05) compared with the other TSER genotypes. CONCLUSION These results suggest that TSER polymorphisms do not predict tumoral TS levels possibly depending on altered TS regulation in cancer tissues, and might explain the lack of clear correlation with clinical outcome after chemotherapy with fluoropyrimidines. However, the relationship between TS phenotype and TSER genotype in normal tissues warrants further investigations in large-scale prospective studies evaluating TS genotype and fluoropyrimidine tolerability.

Thymidylate synthase and dihydropyrimidine dehydrogenase mRNA expression after administration of 5-fluorouracil to patients with colorectal cancer

This study explores the effect of 5‐fluorouracil (5FU) exposure on mRNA levels of its target enzyme thymidylate synthase (TS) and the rate‐limiting catabolic enzyme dihydropyrimidine dehydrogenase (DPD) in tumors of colorectal cancer patients. TS and DPD mRNA levels were determined in primary tumor and liver metastasis samples from patients who were either not pretreated (n = 29) or given one presurgery bolus of 5FU (n = 67). In both groups a wide variation in TS mRNA levels was observed. Median TS mRNA expression in 17 primary tumors of exposed patients was 3.0‐fold higher than in 19 primary tumors of unexposed patients (p = 0.015). TS mRNA expression in liver metastasis samples of exposed patients (n = 16) was also higher (5.2‐fold) than that of unexposed patients (n = 48; p < 0.001). Also DPD mRNA expression displayed a large degree of interpatient variation. No difference in DPD expression in liver metastasis samples was observed between exposed and unexposed patients. However, median DPD mRNA expression in 15 primary tumors of exposed patients was 3.2‐fold lower than in 18 primary tumors of unexposed patients (p = 0.027). In conclusion, administration of 5FU in vivo influences the gene expression of TS and DPD.

Role of Platelet Derived Endothelial Cell Growth Factor/Thymidine Phosphorylase in Fluoropyrimidine Sensitivity and Potential Role of Deoxyribose‐1‐Phosphate

Thymidine phosphorylase (TP) catalyzes the phosphorolytic cleavage of thymidine (TdR) to thymine and deoxyribose‐1‐phosphate (dR‐1‐P). TP, which is overexpressed in a wide variety of solid tumors, is involved in the activation and inactivation of fluoropyrimidines. We investigated the role of TP in 5′‐deoxy‐5‐fluorouridine (5′DFUR), 5‐fluorouracil (5FU) and trifluorothymidine (TFT) sensitivity. TP had no effect on TFT while it activated 5′DFUR and to a lesser extent 5FU. In order to provide an explanation for this difference in activation of 5′DFUR and 5FU, we studied the role of the 5FU co‐substrate, dR‐1‐P, needed for its activation.

Homing and clonogenic outgrowth of CD34+ peripheral blood stem cells: A role for L-selectin?

OBJECTIVE After transplantation of hematopoietic stem cells, adhesion molecules play a major role in the multistep process of engraftment in which L-selectin is suggested to be of relevance. A positive correlation previously was found between the number of reinfused L-selectin(+) stem cells and platelet recovery. In the present study, we determined the role of L-selectin in different engraftment steps, i.e., adhesion to endothelial cells, migration, and clonogenic outgrowth by in vitro assays that closely mimic the in vivo situation. MATERIALS AND METHODS Flow adhesion and migration experiments were performed using the human bone marrow endothelial cell line 4LHBMEC and isolated peripheral CD34(+) cells with or without blocking of L-selectin-ligand interaction. Various clonogenic assays, including serum-free colony-forming unit-megakaryocytes (CFU-MK) and burst-forming unit-megakaryocytes (BFU-MK), were performed with sorted L-selectin(+)L-selectin(-) cells or in the presence of antibodies. RESULTS Blocking of L-selectin on CD34(+) cells did not significantly affect rolling over and firm adhesion to 4LHBMEC. In addition, no role for L-selectin was found in transendothelial migration experiments. Finally, in clonogenic outgrowth of sorted or anti-L-selectin monoclonal antibody-incubated CD34(+) cells, no key role for L-selectin expression could be defined in BFU-MK and CFU-MK assays. CONCLUSION Using in vitro assays for CD34(+) stem cell adhesion, migration, and clonogenic capacity, we were not able to define a major role for L-selectin.

Pharmacology of the paclitaxel–cisplatin, gemcitabine–cisplatin, and paclitaxel–gemcitabine combinations in patients with advanced non-small cell lung cancer

Purpose: To compare the pharmacology of the paclitaxel–cisplatin, gemcitabine–cisplatin and paclitaxel–gemcitabine combinations in patients with advanced non-small cell lung cancer (NSCLC). Patients and methods: Twenty-four chemo-naive patients with advanced NSCLC were randomized to receive one of the three regimens. Plasma pharmacokinetics and pharmacologic parameters in mononuclear cells were compared and related to toxicity and efficacy. Results: Pharmacological parameters of gemcitabine and cisplatin were not influenced by the combination with one of the other agents, while the paclitaxel clearance was significantly lower for the combination with cisplatin as compared to gemcitabine (P=0.024). The percentage decrease in platelets was significantly higher for the gemcitabine combinations (P=0.004) and related to the dFdCTP-Cmax (P=0.030). Pharmacologic parameters were not related to response or survival. Conclusions: Gemcitabine and cisplatin pharmacology were not influenced by the combination with one of the other agents, while paclitaxel has a lower clearance in combination with cisplatin as compared to gemcitabine.